Document Detail


Post-exercise assessment of cardiac repolarization alternans in patients with coronary artery disease using the modified moving average method.
MedLine Citation:
PMID:  19324258     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: We sought to evaluate the utility of T-wave alternans (TWA) assessment in the immediate post-exercise period to identify and validate cutpoints for the modified moving average (MMA) assessment method. BACKGROUND: The presence of TWA is associated with an increased risk of cardiovascular death (CVD). The immediate post-exercise period, where increased physiologic stress and minimal surface artifact coexist, appears ideal to implement the MMA method. METHODS: A test (n = 322) and validation cohort (n = 681) provided 1,003 patients with coronary artery disease (CAD). We assessed TWA immediately after exercise. The outcomes, CVD and mortality, were adjudicated independent of the TWA results. RESULTS: During 48 months of follow-up 85 deaths, 54 categorized as CVD (64%), were observed. A linear relationship between the magnitude of TWA and the risk of CVD was identified. As a continuous measure TWA voltage was equivalent to ejection fraction in predicting the risk of CVD. To facilitate clinical application, a sensitive, modest predictive accuracy (20 microV) and a specific, greater predictive accuracy MMA cutpoint (60 microV) were identified and validated. Each cutpoint was associated with a 2.5-fold greater risk of CVD, independent of other important variables, including ejection fraction. CONCLUSIONS: Post-exercise assessment of TWA using the MMA method is a strong, independent predictor of risk in patients with CAD. The 20-microV cutpoint (87% sensitivity) appears to be most suitable in higher-risk patients, whereas the 60-microV cutpoint (95% specificity) appears more appropriate when TWA is used as a single screening test in those at lower risk. (Assessment of Noninvasive Methods to Identify Patients at Risk of Serious Arrhythmias After a Heart Attack; NCT00399503).
Authors:
Michael P Slawnych; Tuomo Nieminen; Mika Kähönen; Katherine M Kavanagh; Terho Lehtimäki; Darlene Ramadan; Jari Viik; Sandeep G Aggarwal; Rami Lehtinen; Linda Ellis; Kjell Nikus; Derek V Exner; ;
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  53     ISSN:  1558-3597     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-03-27     Completed Date:  2009-04-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1130-7     Citation Subset:  AIM; IM    
Affiliation:
Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
Data Bank Information
Bank Name/Acc. No.:
ClinicalTrials.gov/NCT00399503
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MeSH Terms
Descriptor/Qualifier:
Aged
Coronary Disease / mortality*,  physiopathology*
Electrocardiography
Exercise / physiology*
Exercise Test
Female
Humans
Male
Middle Aged
Predictive Value of Tests
Prognosis
Risk Assessment

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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